The use of balloon catheters is a preferred therapeutic method for a wide variety of indications in many areas of medical technology. In angioplasty and cardiology, for example, a dilation of constricted blood vessels by way of balloon dilation is proposed, releasing restenosis-inhibiting drugs at the same time. According to one variant, for this purpose the drugs are applied directly onto the balloon to be dilated. However, it has been found that in practice up to 80% of the adhering drug is not applied at the desired location of the vessel, but instead is dissolved beforehand by the body fluid present in the lumen and carried away. This increases the risk of undesirable systemic side effects of the drugs.
As a counter measure, it has been proposed, for example, to conduct the expansion of the balloon catheter over a dumbbell-shaped intermediate stage, in which the two ends of the balloon catheter shield the intermediate region coated with drugs from the lumen of the vessel. Thereafter, the balloon is fully expanded. Such a dumbbell-shaped balloon catheter used as an intermediate stage, however, is very complex to produce and handle and therefore prone to failure. In addition, it is impossible to prevent the drug from being rinsed out when irregular vessel geometries came into play.
A different approach would be to apply a coating receiving or covering the drug. The production of such a coating, however, is complex and catheters coated in this manner generally cannot be stored for a long time. The coating material must be biocompatible, and the properties of the drug and the coating system must be matched to each other in each individual case. In practice, this makes the implementation of such a drug-coated balloon catheter very complex, and it still does not provide the desired extent of safety for the local administration of the drug.